Electrokinetic Fence

In 1989, a related technology of cleanup and barrier combined was described by Lageman, Pool, and Seffinga (Fig. 16.4). A line of electrodes placed across a plume of pollution was used to clean up the pollutant as it moved toward the electrokinetic fence. The electrodes are operated submerged in an electrode solution, which can be removed for later treatment. Full-scale trials report successful cleanup, approaching 80% (Lageman, 1993). Further details are given in Chapter 19. 

Figure 16.4. Concept of an electrokinetic fence, which is a barrier and cleanup combined (Geokinetics, Inc., Houston,TX) (US EPA, 1997).

Figure 16.25. Possible configuration of electrodes and reactive barrier for an electrokinetic fence (Gregolec, Roehl, and Czurda, 2002). PRB, permeable reactive barrier.

Muntoni A, Ruggeri R, Lynch RJ. (2003). Investigation of an electrokinetic fence for protection against heavy metal contamination in soils. Fourth Symposium on Electrokinetic Remediation—EREM 2003, May 14-16, 2003, Mol, Belgjnm SCK CEN Belgian Nnclear Research Centre, pp. 51-52. 

Nowicki MA, Lynch RJ, Amaratunga G. (2005). Stand-alone solar powered electrokinetic fence for preventing heavy metal pollution of groundwater. Proceedings of the 20th EU Photovoltaic Solar Energy Conference, June 6-10, Barcelona, Spain. 

Figure 17.1. Schematic representation of an electrokinetic fence. Heavy metals and other polar contaminants are captmed in the electrolytes and periodically removed. There were no contamination downstream of the fence area and no disturbance of the groundwater flow...

Electroreclamation in the form of an electrokinetic fence (EKIS ) can be apphed as a passive in situ method to fence off, contain, and remediate groundwater plumes... 

Electrokinetic Fence (EKF). This uses a chain of electrode pairs deployed in the ground to halt the migration of contaminated groundwater from a point source (see Chapter 22). 

Geokinetics International, Inc., has developed other applications for this technology as weU. It can be set up as an electrokinetic ring fence to recover ionic contamination from groundwater as it flows past the electrodes. It may also be used as a soil heating element in conjunction with soil vapor or groundwater extraction to remove organics from soil. 

At the site of chemical laundry, a project with an electrokinetic biofence (EBIS ) started in April 2001. This fence has been installed to disperse nutrients in the ground and groundwater in order to enhance reductive dechlorinization of present perchloroethene (PCE), trichloroethene (TCE), cw-l,2-dichloroethene (C-DCE),... 

Figure 17.2. Schematic representation of an electrokinetic biofence. The enhancement of biodegradation inside and downstream of the fence area was by inducement of nutrients and homogeneous dispersion of nutrients.

VOCs An electrokinetic biofence is designed to remove VOCs in a groundwater plume or to stop their downstream migration. The biofence will stimulate and create optimal conditions for biological activity to dechlorinate VOCs downstream of the fence. In Figures 17.6 and 17.7, the development in concentrations of PCE + TCE and C-DCE + VC is represented. Note that the building of the chemical laundry starts just 1 m south of the nutrient infiltration. 

Electrokinetic biofence (EBF) consists of a row of alternating cathodes and anodes with a mutual distance of 5 m. Upstream of the line of electrodes, a series of infiltration wells were installed, which have been periodically filled with nutrients. The aim of the EBF is to enhance biodegradation of the VOCs in the groundwater at the zone of the fence by electrokinetic dispersion of the dissolved nutrients in the groundwater. After running the EBF for nearly 2 years, clear results have been observed. The concentration of nutrients in the zone has increased, the chloride index is decreasing, and VOCs are being dechlorinated by bioactivity. 

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